FOOT & ANKLE INTERNATIONAL
Copyright © 2010 by the American Orthopaedic Foot & Ankle Society DOI: 10.3113/FAI.2O10.1043
Continuous Infusion Versus Single Bolus Popliteal Block Following Major Ankle and Hindfoot Surgery: A Prospective, Randomized Trial Robin Elliot, MA, FRCSCir&Orth)1; Christopher J. Pearce, FRCS(Tr&Orth), MFSEM(UK)1; Chris Seifert, FRCA1; James DF Calder, MD, FRCSOr&Orth)1'2 Basingstoke, UK and London, UK
ABSTRACT
Key Words: Popliteal; Block; Catheter; Randomized; Trial
Background: Popliteal sciatic nerve blockade is a commonly used technique employed in the management of postoperative pain following foot and ankle surgery. Recent studies have shown that for outpatient surgery, for moderately painful proce dures, a continuous infusion of local anesthesia via an in dwelling catheter for 48 to 72 hours leads to reduced opiate analgesic requirements and improved pain and patient satisfac tion scores. Materials and Methods: A prospective, randomized, double blind, placebo-controlled trial of a continuous infusion of bupivacaine verses normal saline via a popliteal catheter after a single bolus popliteal block for 72 hours after major ankle and hind foot surgery was performed in 54 patients. Results: The average pain scores overall were low (range, 1.1 to 3.6 on a Visual Analogue Scale of 0 to 10) throughout the study period. Statistically significantly lower pain scores with significantly less requirement for supplementary opiate analgesic agents were seen in the treatment group. Conclusion: Despite the statistically significant findings, with such low pain scores in both groups, we believe it remains debatable whether the extra time and cost involved warrants the use of a continuous popliteal blockade over a single bolus injection. Level of Evidence: I, Prospective, Randomized, Controlled Trial 'Department of Trauma and Orthopedic Surgery, Basingstoke and North Hampshire Hospitals NHS Foundation Trust, Aldermaston Road, Basingstoke, United Kingdom. 2 Imperial College School of Medicine Science and Technology, Level 7, Charing Cross Hospital, London, United Kingdom.
No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Corresponding Author: Christopher J. Pearce, FRCS(Tr&Orth), MFSEM(UK)1 Basingstoke & North Hampshire Hospitals NHS Foundation Trust Orthopaedics Aldermaston Road Basingstoke, Hampshire RG24 9NA United Kingdom E-mail:
[email protected] For information on pricings and availability of reprints, call 410-494-4994, x232.
INTRODUCTION Adequately relieving postoperative pain following ankle and hindfoot surgery can be challenging. Conventional anal gesics have significant side effects including drowsiness, nausea, constipation, and gastric irritation. Regional anes thesia, especially peripheral nerve blockade, is becoming increasingly popular.7 The concept is to provide safe and effective analgesia in the perioperative period. This may reduce the need for general anesthesia and lessen the patient's postoperative analgesic requirements, specifically as an opioid sparing strategy. A single bolus block of the peroneal and tibial neurovascular bundles is effective, but is short-lived (typically 13 to 16 hours) and may fail to provide adequate analgesic coverage for the whole postoperative recovery period.15 The technique of using an indwelling catheter can circumvent this problem and studies have suggested that this is an extremely effective method of pain relief. Continuous nerve blockade has been shown to improve postoperative satisfac tion, allow earlier discharge from the hospital and reduce opioid requirements.410·25·26 We report the results of a prospective, randomized, doubleblind, placebo-controlled trial comparing the effectiveness of a single bolus peroneal and tibial nerve block against a bolus and continuous infusion peroneal and tibial nerve block in the management of postoperative pain following ankle and hindfoot surgery. The primary outcome measure was the mean visual analogue score for pain over the first 72 hours. The secondary outcome measure was the requirement for supplemental opioid analgesia. Our null hypothesis was that there would be no difference in outcomes between the two treatment groups.
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Foot & Ankle InternationallVol. 31, No. 12/December 2010
ELLIOT ET AL.
MATERIALS AND METHODS
All patients undergoing surgery for major ankle or hindfoot conditions by the senior author were considered for recruitment into the trial. Exclusion criteria included coex isting peripheral neuropathy and any inability to fill out the questionnaire. The trial was approved by the local Research and Ethics Committee and registered with the European Clin ical Trials Database. Approval was obtained from the Medicines and Heathcare products Regulatory Authority (MHRA) for the use of normal saline infusion as a placebo. The recommendations of Good Clinical Practice (ICHGCP: International Conference on Harmonisation—Good Clinical Practice, effective since 1.17.1997) and Directive 2001/20/EC of the European parliament relating to the imple mentation of good clinical practice in the conduct of clinical trials on medicinal products for human use were respected. The required sample size was determined using the nQuery Advisor package (version 6). A pilot study was performed; 12 patients were compared in two groups, one group receiving single bolus block, the other receiving bolus block plus continuous infusion of local anesthetic. This allowed us to estimate mean and standard deviations of visual analogue scale (VAS) values for pain in the two groups, where 0 repre sents no pain at all and 10, the worst pain imaginable. From this it was calculated that, with a 5% two-sided significance level, a sample size of 25 in each group would have 90% power to detect a difference in mean VAS scores of 3 which we considered to be clinically significant. A total number of 54 (to allow for potential drop-outs or loss to followup) patients were recruited. Intention to treat analysis was used. Recruitment took place in the settings of the outpatient department and in the pre-assessment clinic. The patients were given a leaflet explaining the aims and objectives of the trial including the potential benefits of the trial and what their involvement would entail. Fully informed written consent and permission for inclusion into the trial was obtained. Patients were all made aware that they were free to withdraw from the trial at any time without having to give a reason. The patients and the assessors were blinded to the treat ment allocated. Sealed envelopes were sequentially used for randomization. These were opened by the anesthetist and the allocation recorded in a file, held by the anesthetic depart ment. No circumstances were foreseen whereby a patient would need to be unblinded other than at their own request. In all, 54 surgeries were performed: 13 ankle fusions, 12 hindfoot fusions, 12 total ankle replacements, seven tibialis posterior tendon reconstructions (calcaneal osteotomy, spring ligament reefing and flexor digitorum longus transfer), five tibiotalocalcaneal (TTC) fusions, three pantalar fusions, and two complex tendoachilles reconstructions (Table 1).. Catheter insertion The block was performed in the anesthetic room, with the patient in the supine position, after the induction of
Table 1: Breakdown of the Surgical Procedures in the Two Groups Operation Ankle arthrodesis Hind/mid foot arthrodesis Ankle replacement Calcaneal osteotomy + tendon transfer Tibio-talo-calcaneal arthrodsesis Pan-talar arthrodesis Tendo-Achilles reconstruction
Study Control 6 6 6 4 3 1 1
7 6 6 3 2 2 1
Fig. 1: Catheter inserted and secured with the infusion device connected.
general anesthesia. The skin was prepared and the anatomical landmarks identified. A 10-cm stimulating needle (B. Braun Medical Inc., Allentown, PA) was inserted horizontally immediately anterior to the biceps femoris tendon at the level of the superior pole of the patella and angled 45 degrees cephalad. The optimal position that we aimed for was with twitches from the nerve stimulator disappearing at 0.6 mA. The bolus block (20 ml 0.5% bupivacaine) was injected and then the indwelling catheter inserted through the needle up to the 5cm mark. The needle was withdrawn and the catheter secured using a Tegaderm™ dressing (Smith & Nephew, Hull, UK) and connected to an infusion device (Stryker PainPump II, Stryker Corporation, Kalamazoo, MI). All patients also received an injection of 10 mis 0.5% Bupivacaine subcutaneously at the medial aspect of the knee to block the saphenous nerve (Figure 1). Treatment protocols Both groups received an initial 20 ml bolus of Bupi vacaine 0.5%. The Control Group (CG) then received a continuous infusion of 0.9% normal saline for 72 hours (4 ml/hr with 1 ml patient controlled bolus/hr). The Trial
Copyright © 2010 by the American Orthopaedic Foot & Ankle Society Downloaded from fai.sagepub.com at American Orthopaedic Foot & Ankle Society on January 3, 2016
Foot & Ankle InternationallVol.
31, No. 12/December
2010
POPLITEAL
Group (TG) received a continuous infusion of 0.25% Bupivacaine (4 mL/hr with 1 ml patient-controlled bolus/hr) for 72 hours. A thigh tourniquet was used for all cases at 300 mm Hg for a maximum of 2 hours. The patients were asked to fill in a visual analogue pain chart, three times daily, for 72 hours postoperatively. Data was also recorded regarding supple mentary opioid analgesia requirements and any problems or complications regarding the catheter. Pain charts and relevant data were collected at the 2-week visit to clinic. Statistical analysis of the results was performed using MedCalc for Windows, version 9.6.4 (MedCalc software, Mariakerke, Belgium). A Mann-Whitney U test was used for the non-parametric data sets.
CATHETER PRCT
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Table 3: Morphine Usage on the Three Postoperative Days Day Study Median Morphine (mg) Control Median Morphine (mg) p value (Mann-Whitney test)
1
2
10
10
15
20
0.054
